Lesson objective: Understand that the mean absolute deviation is the mean distance from each data point in a given set to the mean of the data set.

Students bring prior knowledge of calculating the mean from 6.SP.3. This prior knowledge is extended to measures of variation as students calculate the mean absolute deviation. A conceptual challenge students may encounter is understanding the mean absolute deviation as the average distance from the mean.

The concept is developed through work with a bar chart, which visually depicts the distance to the mean.

This work helps students deepen their understanding of operations because calculating the mean absolute deviation requires the use of subtraction, addition, and division.

Students engage in Mathematical Practice 1 (Make sense of problems) as they persevere through calculating the mean absolute deviation.

**Key vocabulary:**

- deviation
- mean
- mean absolute deviation

**Special materials needed:**

- none